xport-js

Library to read in v5/v6 XPORT files using Node.js .

Installation

To add xport-js to your project, run

npm install xport-js
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Usage and Documentation

See the library documentation for details on methods and options available.

import Library from 'xport-js';
// Create a library instance
const lib = new Library('/path/to/ds.xpt');
// Get variable metadata
const metadata = await lib.getMetadata();
// Get dataset records as objects
let records = [];
for await (let obs of lib.read({ rowFormat: 'object' })) {
    records.push(obs);
}
// Output contents of XPT file to CSV file(s)
await lib.toCsv('/outDir/')
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Library.read method

This method return AsyncIterable which can be used in for await ... of statement.

lib.read(options);
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• dsNames List of dataset names to read, by default all datasets are read.
• rowFormat [default=array] Output observation format. array: [value1, value2, value3, ...] object: { var1: value1, var: value2, var3: value3, ... }
• keep [default=[]] Array of variables to keep in the result (case-insensitive)
• skipHeader [default=false] Flag to control whether the first record contains variable names.
• encoding [default=binary] String encoding, default is latin1 (binary). See the list of encodings supported by Node.js.

Library.toCsv method

Creates CSV file(s) in the outDir.

lib.read(outDir, options);
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See read method options description for details.

Library.getUniqueValues

Returns unique values for specified columns in the dataset.

Usage

const lib = new Library('path/to/file.xpt');
const unique = await lib.getUniqueValues({
  columns: ['AGE', 'SEX', 'RACE'],
  limit: 10,           // Optional: max number of unique values per column (0 = no limit)
  addCount: true,      // Optional: include counts for each unique value
  sort: true,          // Optional: sort unique values
  roundPrecision: 0    // Optional: round numeric values
});
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Parameters

• columns (string[]): List of variable names to get unique values for.
• limit (number, optional): Maximum number of unique values per column (default: 0, no limit).
• addCount (boolean, optional): Whether to include counts for each unique value (default: false).
• sort (boolean, optional): Whether to sort the unique values (default: false).
• roundPrecision (number, optional): Rounds numeric values to the specified precision.

Returns

A Promise resolving to an object where each key is a column name and the value is an object with:

• values: Array of unique values for that column.
• counts: (if addCount is true) Object mapping value to count.

Authors

• Dmitry Kolosov
• Sergei Krivtcov

License

This project is licensed under the MIT License - see the LICENSE file for details.